Reveal face-down cards briefly (1s) before swap completes, using
client-side state diffing instead of a separate server message.
Local player reveals use existing card data; opponent reveals use
server-sent card_revealed as a fallback. Defers incoming game_state
updates during the reveal window to prevent overwrites.
Also update YOUR TURN badge to cyan with suit symbols.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>